1. Field of the Invention
The present invention relates to the field of interfaces for electronic devices. More particularly, the present invention relates to an electronic interface between a digital or analog broadcast signal and various combinations of digital and analog electronics devices.
2. Art Background
The simultaneous growth of the cable television industry and the proliferation of various kinds of consumer electronics devices has spawned a need for providing a standard electronic interface between the signal source and the electronic device. Consumer electronic devices contain various features (eg. pictures within pictures) that may not function properly in a cable television environment due to scrambling, encoding or encryption of the cable signal. The United States Congress has mandated that the Federal Communications Commission (FCC) promulgate rules to assure compatibility between televisions, video cassette recorders and cable systems. These rules must be consistent with the need to prevent theft of cable service while providing cable subscribers with the ability to enjoy the full benefit of both the programming available on cable systems, and the functions available on their televisions and video cassette recorders. (See, 47 U.S.C. .sctn.544a, Section 17 of the Cable Television Consumer Protection and Competition Act of 1992).
Thus, consumer electronics and cable television systems should support the use of advanced television features such as pictures within pictures ("PIP"), the option of watching one program while recording another, the ability to record sequential premium channels, and provide for cable security such as encryption devices to prevent the theft of cable signals.
The use of digital broadcasting media adds to the difficulty of devising an electronic interface that performs the above listed functions. Current systems generally support only analog transmissions, and the existing electronic interfaces are not equipped to support digital broadcasts, such as high definition television (HDTV) broadcasts. Further, to support the Congressional mandate, the existing analog consumer electronic devices must be configured to receive these digital broadcasts, and exist in an integrated system with digital consumer electronics products.
The FCC has responded to these challenges with a Decoder Interface Concept. This provides for a television or video cassette recorder to "tune" the channel, a "set back box" to receive the tuned signal, descramble it and provide it to a television, video cassette recorder or other device for display or recording. (See Volume 58, No. 234, page 64541 of the Federal Register, Wednesday, Dec. 6, 1993). The system must also support both digital and analog signals, and allow for communication between the consumer electronics device and the set back box.
The FCC's concept has not yet been implemented in a specific system that satisfies the Congressional goals and will work in an environment of digital broadcasts. As will be described, the present invention provides an interface that supports the Congressional requirements, as well as accommodates future developments of digital video cassette recorders, optical storage devices and digital televisions.